Electromagnetic vibrator



April 4, 1967 SHINOBU MAKINO 3, ,3

ELECTROMAGNETIC VIBRATOR Filed Oct. 22, 1963 5 Sheets-Sheet 1 INVENTOR. 51/11/0 44 Mex y April 4, 1967 SHINOBU MAKINO 3,312,841

ELECTROMAGNETIC VIBRATOR Filed Oct. 22, 1963 v 5 SheetsSheet 2 A INVENTOR. S/w/vaeu Nan/m M Ma c ul

April 4, 1967 SHINOBU MAKINO 3,3 ELECTROMAGNETIC VIBRATOR Filed Oct. 22, 1963 5 Sheets-Sheet 5 April 4, 1967 SHINOBU MAKiNO 3,312,841

ELECTROMAGNET C ViEhAToR 5 Sheets-Sheet 4 I INVENTOR. Wf/N (.5

Filed Oct. 22, 1965 fin A W April 4,1967

Filed 001:. 22, 1963 SHINOBU MAKINO ELECTROMAGNETIC VIBRATOR 5 Sheets-Sheet 5 IN VENTOR. 80 fink o United States Patent 3,312,841 ELECTROMAGNETIC VIBRATOR Shinobu Makino, Tokyo, Japan, assignor to Shinko Electric Co., Ltd., Tokyo, Japan Filed Oct. 22, 1963, Ser. No. 318,046 7 Claims. (Cl. '31015) This invention relates to an improved construction of an electromagnetic vibrator.

Conventional electromagnetic vibrators have been constructed in such manner than an armature receiving an attractive force by an electromagnet is supported on flat or coil springs. The armature is displaced by an attractive force of the electromagnet; the springs are deformed elastically. When the electromagnet releases, the armature is resiliently displaced by the restoring forces of these springs. By a repetition of these actions, the armature is vibrated and the vibration force is transmitted to the material to be vibrated.

In electromagnetic vibrators of such construction, pole faces were provided in order to support the springs; however, these pole faces are subject to breakage by the vibration; further, the armature at times was made to strike against the electromagnet at the time of vibration, which damaged the electromagnet in rnany cases. Even in case the armature was not made to collide with an electromagnet, the effective life of flat springs was short, since the springs struck against the base of the vibrator.

Regandless whether flat springs or coil springs are used, if it is desired to make the impact forces strong, a strong electromagnet was required since the springs themselves had to be made strong.

In addition, when utilizing springs, the constructions were complicated since four or more sets of springs were required.

The object of'this invention is to provide a vibrator in which the pole faces required in case metal springs are used are omitted, and to eliminate the troubles and damage caused by the springs.

It is a. feature of this invention to use a rubber body, or a pair of rubber bodies as the elastic element, thus to simplify its construction extremely and to oifer a low priced electromagnetic vibrator.

It is another feature of the present invention to support the rubber body by a supporting element such as a supporting wall or a supporting frame, or the like such that it is not liable to cause damages in the vibrator. The length of such a supporting wall or a supporting [frame is easy to arrange according to design requirements; thus it is easy to make the rubber body of sufiicient length in the shearing direction and thereby the support of the armature by said rubber body is made easy. Consequently, it is possible to make the weight of the armature sufiiciently large and thus to obtain impact forces which are large.

It is another feature of this invention to make the movable, or armature portion strike the base of the vibrator indirectly, that is through an elastic rubber body, and avoid collision with the electromagnet, so as not to damage the electromagnet, and also so'as to avoid troubles with fatigue of the rubber body.

It is a further object of this invention to construct an electromagnetic vibrator for use in dusty or contaminated 3,312,841 Patented Apr. 4, 1967 surroundings. Accordingly, the side walls to which the elastic rubber body is fixed, are arranged to also form thesides of a fully enclosed unit, to which a simple cover can be secured.

The drawings show the construction of the present invention for the purpose of showing an embodiment without limiting this invention thereto, in which:

FIG. 1 is a longitudinal sectional front view of a first embodiment of the electromagnetic vibrator of this invention,

FIG. 2 is a sectional FIG. 1;

FIGURE 3 is a side view of FIG. 1,

FIG. 4 is a longitudinal sectional front view of a second embodiment,

FIG. 5 is a longitudinal sectional front view of a third embodiment,

FIG. 6 is a sectional FIG. 5,

FIG. 7 is a longitudinal sectional front view of a fourth embodiment,

FIG. 8 is a sectional FIG. 7,

FIG. 9 is a longitudinal sectional front view of a fi fth embodiment, and 7 FIG. 10 is a sectional plan view cut in line D-D of FIG. 9.

In FIG. 1 to FIG. 3, 1 is the frame of an electromagnetic vibrator rnade of cast steel or steel plates. It consists of a nearly rectangular base 2 and side walls 3 :at both ends of said base; at the lower face of the base 2, mounting legs 4, provided with bolt holes 5 and extending outwardly are provided. 6' is an iron core of the electromagnet 6 fixed onto said base 2, being wound wit-h an excitation coil 7, the pole face 8 facing upwardly. 9 is a movable iron armature facing the upper part of the pole face 8. It is fixed by, e.-g. rivets 11 to a holding frame 10 made of cast steel, steel plate, etc. The holding frame 10 has at both its sides flat arms 12 extending downwardly. The arms are parallel with the side walls 3 and in the inside thereof. The lower end of the arm 12 faces a rubber body 14 :adhesively secured on the upper face of a seat 13 projecting from the base 2. 15 is a plate shaped rubber body, forming a yie-ldable elastic means and fixed by an adhesive agent or the like, to seat plates 16 and 17 which are in turn secured by bolts 23 and 24 respectively, to a face of the side wall 3 and the arm .12, respectively, to elastically support the holding frame 10 on the side wall 3 with the yieldable elastic means 15 being stressed only by the weight of said holding frame 10 and the structure such as the armature 9 carried thereby, the latter holding frame 10 thus being carried by the elastic means 15 in a condition hanging freely over the base and electromagnet 6. When the rubber body 15 is supporting the frame body 10 with the vibrator at rest, the end of the arm 12 is spaced by a gap d from the rubber body 14; and the movable armature 9 has a gap D from the pole face 8. The length of gap D is slightly longer than the length of gap d to some extent. 18 is a cover having a backing 19 of felt or other backing material, to cover the periphery of the side wall 3. It is fixed by screws 20 to the side walls at the lower end portion at the left side in FIG. 3;

plan view out in line AA of plan view out in line B-B of plan view cut in line CC of angle 21 is fixed to the outside of the lower end portion of cover 19 at the right side and the angle is tightened 'by screw 22 against mounting seat 25 of the base 2 so that the flat seat 25 of the angle is connected to the mounting legs 4. Thus, the electromagnet portion, the movable armature and the rubber suspension 15 are completely and tightly enclosed.

The electromagnetic vibrator is secured by bolts inserted in the bolt holes of the mounting legs 4 to the body to be vibrated. When excitation coil 7 is energized by, for example a half-wave rectified alternating current, the electromagnet 6 is excited by half-waves of said alternating current and movable iron armature 9 is attracted downwardly. The tips of the arm 12 of the holding frame strike the rubber body 14, and thereby the base 2 transmits impacts to the body to be vibrated. Since the gap D between the movable armature 9 and the face of pole 6 is larger than the gap between the end of the arm 12 and the rubber body 14, the movable iron armature does not strike the electromagnet. Upon movement, the rubber body is being deformed elastically. At the instant when the electric current through the excitation coil 7 becomes zero, the rubber body 15 develops a resilient restoring force and the holding frame 10, and with it, the movable iron armature 9 are restored upwardly. Thus, the vibration of the movable iron armature 9 and the holding frame 10 is maintained and impacts are given continuously to the body to be vibrated.

FIG. 4 shows another embodiment. Steel plates 26 are at both sides of the iron core 6, for example by welding onto the base 2; and the arms 12 of the holding frame 10 are placed at the outside of plates 26. The base 2 extends outwardly beyond the arm 12 and at the far portion, bolt holes 5 are provided. In this case, the length of the holding frame 10 can be made longer than that shownin FIG. 1; and by also making the weight of the movable portion larger, it is possible to increase the impact force to be given to the body to be vibrated.

In FIGS. 5 and 6 the side walls 3 and the arms 12 are parallel to the longer dimension of the electromagnet 6.

It is possible to increase the thickness of the rubber, yet provide for sufficient strength for the Weight of a relatively heavy movable iron armature and holding frame.

FIG. 7 and particularly FIG. 8 show that frames 16' and 17 arranged as a U-shaped section and fixed by bolts 23 and 24,t0 the side walls 3 and the arm 12 to replace seat plates 16 and 17, respectively, of FIGS. 1 to 3. Rubber body 15' likewise is in a U-shaped section, and adhesively secured between the frames 16' and 17. The movable armature and its holding frame are designed to vibrate straight, in a vertical direction in FIG. 7; however, in case the vibration is not completely symmetrical with respect to X -X plane (FIG. 8), or the attractive force of the electromagnet is not sufiicient, for example, a tilting or a wobble will occur about axis Y'Y' (FIG. 7) and impact against the rubber 14 opposite the end of the arm 12 does not always occur properly. This can be eliminated by employing the U-shaped sectional frames 16' and 17 and the U-shaped sectional rubber 15.

FIGS. 9 and 10 show another embodiment of the vibrator structure for the purpose of preventing tilt or wobble of the movable iron armature and the holding frame at the time of vibration. In this construction, both side wall 3 and arm 12 are formed as endless structures, as shown, in cylindrical shape with the same axis, and connected throughout their length by circular rubber body 15". A plurality of seat plates 16" and 17 in arc shape, are provided, preferably with gaps L and M (FIG. 10)

between segments, respectively. The cylindrical rubber body 15" is adhered between the seat plates 16" and 17". The side wall 3 and the arm 12 need not be circular, but may be oval; in this case, of course, a rubber body 15 of oval, cylindrical, shape is used.

Thus, it will be seen that with the structure of the inlimited thereto, but only as defined by the appended claims.

What is claimed is:

1. An electromagnetic vibrator comprising a base and opposed side wall portions extending upward from opposed sides thereof, respectively, an electromagnet fixed onto said base between said opposed side wall portions thereof, a movable armature facing said electromagnet, a holding frame holding said movable armature and having opposed arm portions which extend downward from both sides and face said side wall portions, respectively, while being spaced therefrom, first yieldable elastic means fixed between said arm portions and said side wall portions and supporting said holding frame in a condition hanging freely from said elastic means and said elastic means being stressed only by the weight of said holding frame and movable armature held thereby, second yieldable elastic means fixed onto said base and leaving a first gap with respect to said arm portions, said movable armature facing the pole face of said'electromagnet with a second gap larger than said first gap.

2. An electromagnetic vibrator as claimed in claim 1, and wherein said side wall portions are situated outwardly beyond said arm portions, including a single cover over the peripheral surface of both said side wall portions to form an enclosed structure.

3. An electromagnetic vibrator as claimed in claim 1, wherein said arm portions are situated outwardly beyond said side wall portions.

4. An electromagnetic vibrator as claimed in claim 1, each of said arm portions of said holding frame being of U-shape and partially enclosing said electromagnet, a U-shaped holding plate secured to each of said side wall portions, said first elastic means being of U-shape and adhesively secured between said arm portions and wall portions.

5. An electromagnetic vibrator as claimed in claim 1,.

said side wall portions forming part of a continuous first cylindrical body, said ar-m portions forming part of a second cylindrical body coaxial with said first cylindrical body, said first yieldable elastic means being in cylindrical form and secured between said cylindrical bodies.

6. In an electrical vibrator: a base; a first cylinder extending substantially perpendicularly from said base; an electromagnet having a core extending in a direction substantially parallel to said first cylinder; and armature, said armature being spaced from said electromagnet core by a predetermined distance; and a holding frame to support said armature and including a second cylinder arranged substantially parallel to said first cylinder and being of a diameter different from that of the first cylinder, said cylinders fitting, with clearance, one within the other, and a ring-shaped resilient body located in the clearance between said cylinders and being adhesively secured thereto, said holding frame being supported in a freely hanging position by said resilient body, with the latter stressed exclusively by the weight of said holding frame and said armature supported thereby.

7. In an electrical vibrator: a base; a pair of spaced, U-shaped plates extending substantially perpendicularly from said base; an electromagnet having a core extending in a direction substantially parallel to said U-shaped plates, the U-shaped plates partially encircling said electromagnet core; an armature, said armature being spaced from said electromagnet core a predetermined distance; and a holding frame to support said armature and including a second pair of spaCecL'U-Shaped arms likewise partially encircling said electromagnet core and being arranged substantially parallel to the first-named pair of spaced, U-shaped plates and spaced therefrom, and a pair of U-shaped resilient elements located in the space between the pair of U-shaped plates and U-shaped arms and being adhesively secured thereto, said holding frame being supported in a freely hanging position by said resilient elements, with the latter stressed exclusively by the weight of said holding frame and said armature supported thereby.

References Citedby the Examiner UNITED STATES PATENTS 1/1936 Wurzbach et al. 31029 7/ 1940 Weyandt 31029 8/ 1957 Urschler et a1. 310-29 11/1960 Alvord 3 10--28 9/1962 Kintzel 31015 X FOREIGN PATENTS 4/ 1960 France. 3/1955 Great Britain.

MILTON O. HIRSHFIELD, Primary Examiner. D. F. DUGGAN, Assistant Examiner. 

6. IN AN ELECTRICAL VIBRATOR: A BASE; A FIRST CYLINDER EXTENDING SUBSTANTIALLY PERPENDICULARLY FROM SAID BASE; AN ELECTROMAGNET HAVING A CORE EXTENDING IN A DIRECTION SUBSTANTIALLY PARALLEL TO SAID FIRST CYLINDER; AND ARMATURE, SAID ARMATURE BEING SPACED FROM SAID ELECTROMAGNET CORE BY A PREDETERMINED DISTANCE; AND A HOLDING FRAME TO SUPPORT DAID ARMATURE AND INCLUDING A SECOND CYLINDER ARRANGED SUBSTANTIALLY PARALLEL TO SAID FIRST CYLINDER AND BEING OF A DIAMETER DIFFERENT FROM THAT OF THE FIRST CYLINDER, SAID CYLINDERS FITTING, WITH CLEARANCE, ONE WITHIN THE OTHER, AND A RING-SHAPED RESILIENT BODY LOCATED IN THE CLEARANCE BETWEEN SAID CYLINDERS AND BEING ADHESIVELY SECURED THERETO, SAID HOLDING FRAME BEING SUPPORTED IN A FREELY HANGING POSITION BY SAID RESILIENT BODY, WITH THE LATTER STRESSED EXCLUSIVELY BY THE WEIGHT OF SAID HOLDING FRAME AND SAID ARMATURE SUPPORTED THEREBY. 